Acute Pansinusitis Caused by a Retained Merocel Pack Forgotten for 50 Days: A Case Report With Histopathologic Insights.

Merocel, a polyvinyl acetal sponge, is a nonabsorbable nasal packing material widely used after sinonasal surgery because of its hemostatic efficacy and ease of placement. However, nonabsorbable packing is generally removed within 48 hours to reduce the risks of mucosal injury, infection, and adhesion. A 48-year-old man underwent endoscopic sinus surgery (ESS) for chronic rhinosinusitis at a secondary hospital. The Merocel pack was inadvertently retained for 50 days, resulting in acute pansinusitis with foul odor, postnasal drip, and facial pain. Attempts to remove the packing by traction and irrigation at the secondary hospital were unsuccessful and caused fragmentation of the Merocel. The patient was subsequently referred to our tertiary center, where revision ESS revealed firmly adherent Merocel fragments. Histopathological examination demonstrated inflammatory tissue ingrowth into the porous Merocel structure without bone fragment entrapment or osseous ingrowth. The patient recovered uneventfully, with no recurrence at the 3-month follow-up. Prolonged retention of a Merocel nasal pack may cause acute sinusitis and firm adhesion through inflammatory tissue ingrowth, even without histopathological evidence of bone involvement. Prevention requires timely pack removal, structured follow-up, and comprehensive patient education.